This invention relates to devices and methods for removing excess fluid from articles during a finishing process. More particularly, the invention relates to the use of a high pressure liquid spray to remove excess fluid located on the exterior surface of the article.
In a typical multi-step finishing process, articles are spraYed with various cleaning solutions during the finishing process. The articles are typically conveyed into a cleaning stage and sprayed with the cleaning solution and then conveyed out of that particular stage.
Each cycle of spraying the articles with the cleaning solution comprises one cleaning step. Several cleaning steps are used during a typical finishing process. Each cleaning step is followed by a rinse step so that excess cleaning solution can be removed from the article prior to a subsequent cleaning step. A conveyor then transports the article to the next cleaning stage to proceed with the next cleaning step.
Rinsing of the articles occurs in a rinse stage or sPray wash booth and serves to reduce carryover of cleaning solution between separate solution tanks. A common Problem with such rinse operations is that excess rinsing fluid may be retained on the exterior surface of the article as the article exits the rinse operation. This is particularly a problem for articles having upwardly turned edges which form cavities on the top surface of the article because such a configuration permits substantial retention of excess rinsing fluid. The excess fluid can be carried to a subsequent solution tank causing contamination of the subsequent cleaning solution which is undesirable.
In addition to being desirable to prevent contamination of the cleaning solution, removal of excess fluid from the exterior surface of articles is necessary when containment of the cleaning solution is required. Many cleaning solutions are highly toxic, and containment of the cleaning solution may be required for environmental reasons. In addition, cleaning solutions are often expensive. Therefore, the overally cost of cleaning the article can be reduced if excess cleaning solution is recovered and reused.
Excess fluid on the exterior surface of articles also increases the time and energy required to dry the articles after the finishing process is complete. When a drying operation follows a rinse step, it is desirable to minimize the excess fluid retained on the exterior surface of the articles in order to save drying time and energy costs.
It is known in the art to use water sprays for rinsing a cleaning solution from an article. It is also known in the art to use forced air to remove fluid from the exterior surface of articles after the articles have been rinsed. The present invention increases the efficiency of removing excess fluid from articles by utilizing a high pressure liquid spray to force the excess liquid off the article.
One object of the present invention is to eliminate solution carryover on the exterior surface of articles from one finishing step to the next to prevent contamination of separate tanks of cleaning solution used in a multi-step finishing process.
Another object of the present invention is to reduce excess fluid on the exterior surface of an article prior to drying the article to reduce the time and energy required to dry the article.
According to the present invention, an apparatus is provided for removing excess fluid from an article. The apparatus includes a housing, means for spraying a high pressure liquid stream across a predetermined area inside the housing, and means for supplying liquid to the spraying means. The apparatus further includes means for transporting the article having excess fluid on a portion of its exterior surface through the housing so that the portion of the exterior surface of the article having excess fluid thereon passes through the high pressure liquid stream. The high pressure liquid stream forces substantially all the excess fluid off the outer surface of the article.
In preferred embodiments, the spraying means includes a spray nozzle coupled to a liquid supply pipe. A pump forces the liquid through the supply pipe and nozzle at a predetermined discharge pressure. The pressure is selected to be high enough so that the liquid spray forces excess fluid from exterior cavities formed on the article without refilling the cavities with liquid from the fluid removing apparatus. As the article is transported past the high pressure liquid spray, the liquid spray sweeps substantially all the excess fluid from the exterior surface of the article. The velocity of the liquid spray is high enough so that only a small quantity of the liquid remains on the article's exterior surface after the article passes through the high pressure liquid spray.
One feature of the invention is the provision of a high pressure liquid spray nozzle positioned so that articles are transported through the high pressure liquid spray from the nozzle after the articles have been sprayed with a cleaning solution and rinse. Advantageously, such a configuration removes substantially all the excess rinsing fluid from the exterior surface of the articles, thereby minimizing the risk of contamination of cleaning solution in a subsequent solution tank and reducing the time and energy required to dry the articles.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.